He proved that when so syntonized the circuits are inductively respondent to each other with a much less power expenditure in the primary circuit than without the syntony.
Fleming devised an arrangement in which a multiple transformation takes place, two oscillation circuits being interlinked inductively, and the last one acting inductively on the open or antenna circuit.
It can be shown that if two circuits, both having capacity (C) and inductance (L), are coupled together inductively, then, when oscillations are set up in one circuit, oscillations of two periods are excited in the other differing in frequency from each other and from the natural frequency of the circuit.
Wave motion the wave-length A is connected with the frequency n and the velocity of propagation v by the relation v=nA, it follows that from such an inductively coupled tuned antenna electric waves of two wave-lengths are sent out having lengths X and such that A = (1 - k) and / (1 ±k), where A is the natural wave-length.
In many cases additional condensers or inductance coils are inserted in various places so that the arrangement is somewhat disguised, but by far the larger part of the electric wave wireless telegraphy in 1907 was effected by transmitters having antennae either inductively or directly coupled to a closed condenser circuit containing a spark gap.